Glycoengineered Type II Anti-CD20 Monoclonal Antibody Pregnancy: US label §8.1: based on findings from animal studies and its mechanism of action, obinutuzumab can cause fetal B-cell depletion. There are no data in pregnant women to inform a drug-associated risk; monoclonal antibodies are transferred across the placenta. In pregnant cynomolgus monkeys dosed from day 20 of pregnancy until parturition at exposures up to 2.4 times the clinical exposure at 1,000 mg monthly, opportunistic infections and immune-complex-mediated hypersensitivity reactions occurred, but no embryo-toxic or teratogenic effects were seen. Advise pregnant women of the potential risk to the fetus. Pregnant women with systemic lupus erythematosus are themselves at increased risk of adverse pregnancy outcomes. (US labelling — verify against the UK SPC §4.6.)

Obinutuzumab (Anti-CD20 — Lupus Nephritis)

Brand names: Gazyvaro

Obinutuzumab is a humanised, glycoengineered type II anti-CD20 monoclonal antibody given by intravenous infusion; in this context it is being used to deplete B cells in lupus nephritis, where it has been studied alongside standard immunosuppression.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Active lupus nephritis: 1,000 mg by intravenous infusion at the initial infusion, then at Week 2, Week 24 and Week 26, and every 6 months thereafter

Route: Intravenous infusion only, through a dedicated line. Do not administer as an intravenous push or bolus.

Frequency: Initial infusion, Week 2, Week 24, Week 26, then every 6 months

NO UK SPC (eMC) WAS RETRIEVED IN THIS BUNDLE — the regimen above is taken from the US FDA prescribing information for GAZYVA (Genentech, Inc.; label date 2025-12-19; https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=47afa519-4a05-4ac2-8604-437371837128). VERBATIM (Highlights, §2.4): 'The recommended dosage for active lupus nephritis is 1,000 mg at the initial infusion, on Week 2, 24, 26, and every 6 months thereafter.' IMPORTANT — THE DETAILED LUPUS NEPHRITIS SECTION (§2.4) WAS TRUNCATED AT THE SOURCE-FETCH LIMIT: the lupus-nephritis infusion rates, the specific premedication schedule for LN and any LN-specific background immunosuppression were NOT retrieved. Do not assume the oncology infusion rates apply to lupus nephritis — the clinician must confirm these against the full label and the UK SPC. GENERAL DOSING (§2.1): premedicate before each infusion; provide prophylactic hydration and anti-hyperuricaemics to patients at high risk of tumour lysis syndrome; monitor blood counts at regular intervals; administer only under the supervision of a healthcare professional with appropriate medical support to manage severe infusion-related reactions, which can be fatal. PREMEDICATION (§5.3): glucocorticoid, acetaminophen (paracetamol) and an antihistamine — specific doses for lupus nephritis were not retrieved in this bundle. OTHER LABELLED INDICATIONS (for reference, not the page indication): chronic lymphocytic leukaemia — 100 mg on day 1 and 900 mg on day 2 of Cycle 1, 1,000 mg on days 8 and 15 of Cycle 1, then 1,000 mg on day 1 of Cycles 2–6 (six 28-day cycles); follicular lymphoma — 1,000 mg on days 1, 8 and 15 of Cycle 1, 1,000 mg on day 1 of Cycles 2–6 or 2–8, then 1,000 mg every 2 months for up to 2 years. MISSED DOSE (oncology schedules): administer the missed dose as soon as possible and adjust the dosing schedule to maintain the interval between doses. IMMUNISATION (§5): avoid live virus vaccines during treatment. PAEDIATRIC (§8.4): 'The safety and effectiveness of GAZYVA in pediatric patients have not been established' — no paediatric dose is stated, so paedDose is null; verify any under-18 use against a children's formulary. NO §7 DRUG INTERACTIONS SECTION AND NO RENAL DOSING SECTION WERE RETRIEVED IN THIS BUNDLE.

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Known hypersensitivity reactions (e.g. anaphylaxis) to obinutuzumab or to any of the excipients
Serum sickness with prior obinutuzumab use

Side effects

Lupus nephritis — upper respiratory tract infection, COVID-19, urinary tract infection, bronchitis and pneumonia (most common, incidence ≥ 5%; the §6 list was truncated at the source-fetch limit)
Infusion-related reactions — premedicate; interrupt, reduce the rate or discontinue based on severity. Hypersensitivity reactions including serum sickness require permanent discontinuation
Neutropenia and thrombocytopenia — monitor blood counts; consider dose delays and infection prophylaxis for Grade 3–4 neutropenia; transfusion may be necessary for thrombocytopenia
Serious, including fatal, infections — do not administer to patients with an active infection; patients with recurring or chronic infections may be at increased risk
Hepatitis B virus reactivation and progressive multifocal leukoencephalopathy
Tumour lysis syndrome (in CLL and FL) and disseminated intravascular coagulation

Clinical monograph

How it works

It binds CD20 on B lymphocytes and triggers profound B-cell depletion predominantly through direct cell death and antibody-dependent cellular cytotoxicity, with comparatively less complement-dependent cytotoxicity than type I anti-CD20 agents.

Prescribing in practice

Screen for hepatitis B (HBsAg and anti-HBc) before treatment because B-cell depletion can reactivate hepatitis B, sometimes fulminant — withhold in active infection and arrange specialist monitoring/prophylaxis for past exposure.
Infusion-related reactions are common, particularly with the first infusion, so give premedication and infuse with appropriate monitoring and resuscitation facilities available.
Prolonged B-cell depletion increases infection risk, including the rare possibility of progressive multifocal leukoencephalopathy, so investigate new neurological or persistent infective symptoms promptly.

Monitoring

Monitor full blood count for cytopenias, watch for infection and infusion reactions, and remain alert to hepatitis B reactivation and new neurological signs throughout and after the treatment course.

Counselling the patient

Report fever, sore throat or other signs of infection without delay.
Tell us about any new confusion, weakness or changes in vision.
Live vaccines should be avoided while your B cells are suppressed.

Evidence & guidelines

Use in lupus nephritis is supported by controlled trial data showing improved renal responses when added to standard care, though it remains a specialist-initiated, off-label or emerging indication in the UK.

Reference: Jayne et al. NEJM 2022 (NOBILITY trial); MHRA Gazyvaro SPC; BSR SLE Guidelines 2023; FDA Breakthrough Therapy Designation for obinutuzumab in LN 2023; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways